Wood-fiber board



pril 2L. 1925. a

' J. K. SHAW woov FIBER BOARD Filed May 25, 19 18 aftozncq Patented Apr. 21 1925.

I v 1,534,0 UNITED STATES PATENT OFFICE! JOHN K. SHAW, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO B. G. DAHLBERG, OF

' ST. PAUL, MINNESOTA.

WOOD-FIBER BOAR-D.

Application filed May 23, 1918. Serial No. 236,161.

To all whom it may concern:

l 3e it known that I, JOHN K. SHAW, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in VVood- Fiber Boards; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention pertains to a board or panel of the class commonly known as plaster-boards, because designed to serve as -a base upon which to carry a layer or coating of plaster, cement, or stucco, suitable for interior or for exterior walls of buildings, and for other structural uses.

The board or base is formed mainly of disintegrated Vegetable fiber, largely the tailings or screenings of ivood-pulp paper stock, too coarse for the manufacture of paper, and heretofore commonly treated as refuse or waste material. In practice it is preferred to use the product known and sold under the registered trade name or trade mark Insulite. This product is primarily designed as a thermo-insulating material, and its properties and the mode of its manufacture are set out in Letters Patent of the United States granted and issued to Carl Muench, September 14, 1915, and numbered 1,153,512. It is therein described as extremely light, tough, flexible,

' of great tensile strength, and containing countless air cells, hence constituting an ideal non-conductor, well adapted for struc tural purposes. Owing to its porosity, its felted formation, and fibrous texture, plaster applied to its surface adheres tenaciously thereto, entering more or less into the same to a slight depth.

In order to secure the desired thickness of sheet or slab, successive layers of the pulp screenings, with water, are in practice superposed and felted together, 'lightly pressed, and finally dried, out into suitable lengths or sizes, and these are used 1n lieu of lathing, expanded metal, and like foundations for plaster, cement, stucco, and other surface coatings.' Owing to this lammate structure, it has been feared by some builders and architects that in use, particularly for outside walls exposed to the elements, the outer layer or layers might, under the Weight of the cement or stucco coating, separate and fall away from the inner layers,

and in fact many doubted the adequate adhesion of plaster to such a surface, even for lndoor use, These fears have proven to be ,without substantial basis, though in certain separation might v the surface of the board. pressure being applied to the more or less fluid plaster, cement, stucco, or like material, and thereby forcing it to flow into and fill the cavities, recesses, or holes. Owing to the porosity of the board or base, the air is enabled to escape from the cavities as the plaster enters and fills them, and, due to the fibrous and porous character of the walls of the cavities the plaster efi'ectively attaches itself thereto. The plaster, cement, or stucco also adheres to the face of the board or base for like reasons.

To further ensure the bonding together of the laminae and preclude any withdrawal of the lugs, keys, or studs from their seats in the board or base, the cavities, recesses or holes are undercut, or have their walls inclined relatively to the face of the board, and in diiferent directions. They may be of uniform cross section but pointed in divergent directions, or made of frusto-pyramidal form, increasing in cross section toward their inner ends or towardthe rear wall of the board or' base. a

The employment of lugs, keys or studs of relatively small cross section rather than long or continuous ribs or bars of dovetail section, is desirable because -suchlugs afford adequate bonding or holding capacity, yet do not greatly or materially impair the insulation value of the board, their aggregate area being small in proportion to the area of, the board; and finally, the lugs, keys or studs do not materially weaken the board or base. The cavities will be made with a mouth or open end of suflicient size to permit the ready entrance of the plaster, cement, stucco, or, like surfacing material, but preferably not larger than will insure such entrance. As the board is primarily used because of its heat-insulating proper- :tfiest, the importance of this feature is manies I Referring to the accompanying drawings forming a part of this specification in which like numerals designate like parts in all the views:

Figure 1 is a plan view of a block or slab of Insulite material showing its larger fibers somewhat exaggerated;

Figure 2, is a sectional view of the material shown in'Figure 1;

Figure 3 is a view of the block or slab shown in Figure 2 with a plastic material applied thereto;

Figure 4 is a View of a block or slab similar to that shown in Figure .1 but having a different kind of cavity or depression therein;

Figure 5 is a sectional View of the block or slab shown in Figure 4; and

Figure 6 is a view of the block or slab shown in Figure 5 with a plastic. material applied thereto.

In order that the precise invention may be the more clearly understood, it is said: The board, or Insulite material from which the block, panel, or board 1, is preferably made, is partly composed of quite large fibrous pieces, or slivers 2,.oecas1onally as much as 1/8 of an inch wide and 1/2 inch to one inch -long.- Mixed with these slivers 2 is a second class of string like fibers 3 which are say 1/32 to 1/64 of an inch in diameter and 1 inch or 2 inches long.' Mixed with the fibers 2 and 3 is a third class ofhair like fibers lwhose diameters are say, from 1/100 to 1/200 of an inch and which are sometimes 1 or 2 inches long, although they vary greatly in length: And mixed with fibers 2, 3 and 1 is a fourth class of 'fibers such as those used in the making of paper of coarser and of finer grades, for which the paper-pulp screenings used in Insulite would be unsuited. These various fibers are compressed and felted together,

when owing to the very great diflerences in their coarseness, the resulting board, tile, block or panel is found to be $0 porous that it resembles cork in its lightness and heat insulating properties. In fact, the specific gravi y of Insulite is often well below three tenths, although it varies with the raw material and manner of making. In all cases, however, it is so porous that plaster, cement and other like plastics, may enter its interstices to a greater or less extent and thus bond with the same. On the other hand, as the Insulite material is made .in a manner very similar to paper board by flow- 1,5s4,oss

ing one layer of pulp upon another, its body portion exhibits a layer formation, and therefore plastics adhering to the surface of said material might if strongly pulled upon flake off one or more layers of Insulite, and thus eifect a complete separation of thetend below the surface they widen out as indicated at 6, to form anundercut or under pressed out surface as shown.

-Owing to the very coarse nature of the fibers 2 and 3 above mentioned the surfaces 6, are more or less rag ed, and afford nulnerous interstices into which the plastic material 7 may enter as indicated at 8. The result is said plastic material 7 not only obtains a firm hold on the Insulite 1 but it permeates and binds together so to speak the layer like structure of said Insulite, thus making a firm and permanent board.

In the somewhat modified form of the invention shown in Figures 4: and 6, thematerial is the same as in the preceding figures, but the holes 10 are of a different shape and are slanted in different directions as indicated by the full and dotted lines in Figures 4 and 5. The bonding action of the plastic material 7 however, is the same as in the preceding figures, in "that said material penetrates between the fibers to a greater or less extent as indicated at 12, and thus firmly binds the layer like structure together.

It will thus be observed that I am enabled, by following the procedure outlined, to produce a panel, block, slab, tile, etc., consisting of Insulite material with a plastic material firmly anchored thereto, and that these articles are capable of general use. It will also be clear that the block, slab or panel 1 of Insulite shown in Figures-1 and 4. is capable of use alone in forming the interior surfaces of walls and buildings or in other relations where it is desired to apply'plaster like materials to a substance simulating the physical properties of cork.

It is further observed that I am enabled, by following the procedure outlined, to produce a panel, block, board, etc., which is composed of disintegrated vegetable fiber pulp, and which is formed with depressions adapted to positively interlock with a plaster applied thereto. Further, the fiber pulp being so porous it is adapted to stretch and compress so readily that it will not offer sufficient-resistance to crack the plaster when the latter expands.

Accordingly it is obvious that those skilled in the art may vary the details of construc tion as well as the relations of the parts 1 without departing from the spirit of the invention. Therefore, I do not wish to be limited to the above disclosure, except as may be required by the claims.

' What I claim is 2- 1. As a new article of manufacture a porous body of paper board material, containing coarse, fine and intermediate sized fibers disposed in layers, said body having a specific gravity of less than four tenths, and provided with a plurality of hbles having ragged surfaces adapted to receive and anchor a plastic substance, substantially as described.

2. As a new article of manufacture a porous body of paper board material, containing sliver like and string like fibers mixed with other finer fibers disposed in layers, said body having high heat insulating properties and a specific gravity less than four tenths; and having adhering thereto and penetrating the pores thereof a layer of a plastic substance, substantially as described. 7 Y L 3'. As a new article of manufacture a I porous body of paper board material, containing sliver-like and string like fibers mixed with other finer fibers disposed in layers, said body having high heat insulating properties and a sp ific gravity less than four tenths; said bo y also provided with holes having ragged edges extending in: an inclined direction under its surfaceand having adhering thereto and penetrating the pores thereof a layer of a plastic substance,

heat-insulating wall-board formed mainly;

of disintegrated vegetable fiber, and having numerous relatively small recesses extending from its plaster-receiving face inward well matinee vegetable fiber, having a series of recesses extending from its plaster-receiving face inward, the walls of said recesses being oblique and at divergent angles to the plaster-receiving surface. Z

9. A porous, compressible and resilient heat-insulating wall-board of disintegrated vegetable fiber, having a series of recesses extending from its plaster-receiving face inward, the walls of said recesses being oblique and at divergent angles to the plaster-receiving' surface; and a layer of plastic material covering the outer face of the board and entering the recesses, .substantially as described.

10. A wall-board formed disintegrated vegetable fiber, and having itslplaster-receiving face provided with reces es extending inward toward the rear face of the board, their wallsbeing oblique to said face; whereby said board is adapted to receive a layer of plastic material which, flowing into such recesses and forming lugs or keys, will be firmly anchored to the board.

11. A wall-board formed of disintegrated vegetable fiber, and having its plaster-receiving face provided with recesses extending inward toward the realm-face of theboard, their .walls being oblique to said face; and a coating of plastic material applied and adheringto the surface of said board, and anchored thereto by lugs or keys of plaster integral with the surface coating.

In testimony whereof I affix my signature.

Joan K, SHAW. 

